Grammar is that part of writing that is dry and nit-picky. But oh, how annoying it is when you come across bad grammar in writing! By necessity, then, grammar is instrumental in the education of writing.
It was only when I started studying Spanish did I realize the importance of grammar. None of the rules were natural to me. Whereas in English I would write “I love to run” without thinking twice, I had to learn that in Spanish it is “me encanta correr,” not “me encanta corro.” (Because when two verbs go walking, the first one does the talking, obviously.) By the time I was in Spanish 4 that basic rule of verb tense was second nature. But I distinctly remember being taught that rule for the first time as a freshman and wapping my head around this new way of ordering words into sentences.
Grammar is what anchors a language in continuity and consistency. To a non-English speaker trying to learn English, imagine if your teacher told you that grammar doesn’t matter, it’s about the pure, unadulterated expression of thought. You would be lost trying to string together vocabulary words, stumbling around in the dark failing to see the thread that connects the language. Grammar is one of those rules you can only break well when you know it well to begin with.
Grammar is like music theory for language. Without being taught grammar, language would be like someone teaching a beginner pianist to play Claire de Lune. They would eventually know how to play the song by memorizing which fingers go where at what time, but they wouldn’t know how to read music, they wouldn’t know the first thing about music theory or how to play another song based on the laws of the instrument and music.
There’s a purpose for grammar, and it’s important that we don’t lower our standard for what good grammar is. I’m a fan of using colloquial grammar, but I don’t think we as a society should neglect to teach grammar, because then gradually, the standard for what colloquial grammar is will fall to what we now consider to be bad grammar. And it’s a downward spiral from there.